Faculty of Computer Science

Max Planck Institute - Security and Privacy

Ruhr Universität Bochum

Universitätsstraße

Bochum 44799, Germany.

samuel (dot) crew (at) rub (dot) de

My primary research interests are in information theory and quantum computing. I am currently working on a wide range of problems including neural network simulation of gauge theory; random tensor networks, holography and quantum cryptography; and topological quantum error correction.

My PhD research was in high energy physics and the geometry of (topological) quantum field theory. In this area, I am particularly interested in connections between supersymmetric gauge theories and geometric structures in the spirit of "physical mathematics".

I am also interested in differential/difference equations and applications of resurgence/Borel resummation in both quantum and classical physics and geometry.

Some past and present research interests include:

- Exact results in 3d N=4 topological QFT and 3d mirror symmetry.
- Integrability, enumerative geometry and geometric representation theory in QFT.
- TQFT and knots.
- Resurgence and large width limits of neural networks.
- Borel resummation and Stokes phenomenon in differential and difference equations.
- Classical free surface flows.

Broadly, I like using geometry to understand phenomena in classical and quantum physics and I enjoy the challenge of working on diverse problems across traditional subject divides. I am always happy to chat about any of the above!

- S. Crew, D. Zhang and B. Zhao -
*Boundaries & Localisation with a Topological Twist*(hep-th/2306.16448) - S. Crew, A. Goswami and R. Osburn -
*Resurgence of Habiro elements.*(In review) (math.NT/2304.07001) - S. Crew, J. Shelton and P. Trinh -
*Higher-Order Stokes Phenomenon in Singularly Perturbed ODEs.*(In review SIAP) (math.ca/2303.07866) - S. Crew and P. Trinh -
*Resurgent Aspects of Applied Exponential Asymptotics.*(In review) Studies in Appl. Math. (2208.07290) - S. Crew -
*Geometric Aspects of 3d N=4 Gauge Theories.*(PhD Thesis) - M. Bullimore, S. Crew, and D. Zhang -
*Boundaries, Vermas and Factorisation.*JHEP (2021) 263 (2010.09741) - S. Crew, N. Dorey and D. Zhang -
*Blocks and Vortices in the 3d ADHM Gauge Theory.*JHEP (2021) 234 (2010.09732) - S. Crew, N. Dorey and D. Zhang -
*Factorisation of 3d N=4 Twisted Indices and the Geometry of Vortex Moduli Space.*JHEP (2020) 08, 015 (2002.04573) - S. Crew and P. Trinh -
*New singularities for Stokes waves.*J. Fluid Mech. 798, 256-283 (1510.04254)

*"Analytic continuation for children"*- Seminar talk at Exact Asymptotics OIST (Oct. 2023)*"Parametric resurgence and Borel resummation"*- Seminar at National Taiwan University (Oct. 2023)*"Hemisphere blocks of 3d N=4 gauge theories"*- Seminar NCTS at National Tsing Hua University, Taiwan (Oct. 2023)*"A minimal example of higher order Stokes phenomenon"*- Symposium talk at Exact Asymptotics program OIST, Japan (Sept. 2023)*"A minimal example of higher order Stokes phenomenon"*- Seminar at Tokyo Metropolitan University (Sept. 2023)*"Resurgence for computer scientists"*- Seminar talk at RUB (June. 2023)*"Vortex counting, WKB, and the higher order Stokes phenomenon"*- Seminar talk at OIST quantum gravity (Mar. 2023)*"Resurgence in a toy water wave model"*- Seminar talk at UEA (Dec. 2022)*"Practical parametric resurgence"*- Invited talk at INI ARA program (Nov. 2022)*"Parametric resurgence in nonlinear differential equations"*- Seminar at University College Dublin (Oct. 2022)*"Parametric resurgence and large N vortex counting"*- Seminar at OIST Japan (August 2022) - slides*"Resurgence in quantum field theory"*- 3x1 hour lecture series at Tokyo Metropolitan University (August 2022) - outline*"Resurgence, exponential asymptotics and pathologies in toy water waves problems"*- Bath water waves symposium (June 2022)*"Resurgence and exact WKB"*- BAMC, Loughborough (April 2022)*"Stokes phenomena and Borel resummation"*- Lecture at UEA (November 2021)*"Gauge theory, integrability and curve counting"*- Bath algebra, geometry and number theory seminar (May 2021) - slides*"What is quantum field theory?"*- ARA INI Program mini-course*"Hemisphere blocks in 3d N=4 theories"*- Fudan university (Mar. 2021) - watch*"Factorisation and Vortices in 3d N=4 Theories"*- Kavli IPMU (Nov. 2020) - slides*"Boundaries, Vermas and Factorisation"*- Imperial quiver seminar (Nov. 2020)*"Quivers, Spin Chains and Black Holes"*- DAMTP, Cambridge (Jun. 2018)*"New singularities for Stokes' waves"*- BAMC, Oxford (2016)

A supervision with me as depicted by a student (artist credit @quantumcutie1228)

- MA30044: Mathematical Methods 1

- Classical Dynamics (Part II) Michaelmas 16-17, 17-18, 18-19.
- General Relativity (Part II) Lent 16-17, 17-18.
- Symmetries, Fields and Particles (Part III) Michaelmas 17-18, 18-19, 19-20.
- Mathematical Methods (Part IA Nat. Sci.) 17-18, 18-19, 19-20.
- Mathematical Methods (Part IB Nat. Sci.) 17-18, 18-19, 19-20.
- Quantum Field Theory (Part III) Michaelmas 20-21.

- Autumn 2023 - Exact Asymptotics: From Fluid Dynamics to Quantum Geometry. OIST, Japan.
- October 2023 - Research visit to NTU, Taiwan (Heng-Yu Chen)
- September 2023 - Research visit to YITP, Kyoto (Masazumi Honda)
- September 2023 - Research visit to TMU, Japan (Akira Shudo)
- March 2023 - Quantum Information Theory School. ICMAT, Madrid.
- February 2023 - Quantum Information Processing. Ghent, Belgium.
- September 2022 - Isaac Newton Institute program on applicable resurgent asymptotics (part 2)
- October 2022 - Research visit to UCD Ireland (Robert Osburn)
- July 2022 - University of Bath water waves symposium.
- Various 2022 - Japan: Tokyo metropolitan university, OIST and Kyoto university.
- April 2022 - British Applied Math Conference (Loughborough)
- July 2021 - IHES summer school on enumerative geometry.
- April-June 2021 - Isaac Newton Institute program on applicable resurgent asymptotics (part 1)

I completed my PhD at DAMTP and Trinity college, Cambridge UK in 2021. I studied geometric aspects of quantum field theory and I was supervised by Nick Dorey. Before Cambridge, I was an undergraduate at Lincoln college, Oxford where I studied first for a BA in mathematics (2012-2015) and then an MMathPhys in mathematical and theoretical physics (2015-2016).

Following my PhD I spent 1.5 years as a postdoc working with Phil Trinh in the department of mathematical sciences at the University of Bath. Here I learnt about resurgence and Borel resummation. I worked on a range of problems in quantum and classical physics and geometry.

Following my first postdoc, I then moved to Bochum, Germany to work with Michael Walter and Giulio Malavolta in the computer science department of Ruhr University Bochum and the Max Planck institute for security and data privacy.

Short CV